Table 3.
Biological Activity (IC50) of N-Methylated Cyclic Peptides and Standard Peptides in Inhibiting the Binding of Vn and Fg to Isolated Integrins αvβ3 and αIIbβ3, Respectively
| Peptide | IC50 (µM) αvβ3 | IC50 (µM) αIIbβ3 | Selectivity αIIbβ3/αvβ3 |
|---|---|---|---|
| GRGDSPK | 0.21 | 1.7 | 8.1 |
| c(RGDfV) | 0.0025 | 1.7 | 680 |
| 1, c(-N(Me)R-GDfV) | 0.0055 | 5.2 | 945 |
| 2, c(R-N(Me)G-DfV) | 0.045 | > 10 | n.c. |
| 3, c(RG-N(Me)D-fV) | 0.56 | > 10 | n.c. |
| 4, c(RGD-N(Me)f-V) | 1.4 | > 10 | n.c. |
| 5, c(RGDf-N(Me)V-) | 0.00058 | 0.86 | 1483 |
The selectivity for these receptors is expressed as the ratio between the IC50 values for each integrin subtype [16].